Algebra 2. It had been an easy day so far. They had work. They did it. I spent much of the period seated with occasional strolls around the room.
It was during one stroll that I caught a girl returning a flipped backpack to her neighbor's desk. (The neighbor was sitting in another seat on the other side of the room.) She saw me, and she begged me to keep quiet.
"I haven't seen this in like five years," I said.
At about this time, the boy returned to his seat and found the flipped backpack. He had heard what I said, and he had a response.
"I did this all the time last year."
Then he showed us a new (to me) trick. The girl only flipped the backpack inside out. But, the boy used to take everything out of the backpack and flip it inside out using the front pocket, leaving a "football".
(On a hunch, I Googled this. Turns out there's a YouTube video. Several, in fact.)
Apparently, the prank is still around. I guess I need to pay closer attention. But, then again, I suddenly felt less troubled about the boy getting pranked. I rather think he was due.